Vacuum interrupter and electrical switching device

Abstract

The invention relates to a vacuum interrupter (1). The vacuum interrupter (1) comprises a housing (3) having an electrically conductive connection body (6). The connection body (6) has an external connection geometry (7) for a releasable clamping connection for the electrical and mechanical contacting of the vacuum interrupter (1).

Description

[0001] 2024P18363 DE 1

[0002] Description

[0003] Vacuum switching tube and electrical switching device

[0004] The invention relates to a vacuum switching tube and an electrical switching device.

[0005] A vacuum switching tube comprises a housing and two switching contacts that are movable relative to each other and are arranged within the housing. Typically, one switching contact is a fixed contact, rigidly connected to the housing, and the other switching contact is a movable contact, which is movable relative to the fixed contact between a first switching position, in which it is in contact with the fixed contact, and a second switching position, in which it is separated from the fixed contact.

[0006] A vacuum interrupter tube is used in an electrical switching device and must be mechanically and electrically connected to the switching device. This connection is typically achieved using screw connections and band clamps. For this purpose, internal and / or external threads are created on the terminals of the vacuum interrupter tube. These threads are produced, for example, by machining bolts connected to the switching contacts or by soldering bushings into the bolts. Due to processes involved in the manufacturing of a vacuum interrupter tube, such as electroplating or soldering, the threads are often not dimensionally accurate. Cleaning the threads is also time-consuming. This leads to a correspondingly high testing effort and / or scrap. Furthermore, the process of screwing a vacuum interrupter tube into the switching device is time-consuming.Furthermore, when screwing in a vacuum switching tube, care must be taken to ensure that the body of the vacuum switching tube is not twisted, as this could otherwise lead to a premature end of the vacuum switching tube's service life.

[0007] The invention is based on the objective of providing a vacuum switching tube, which is improved in particular with regard to its mechanical and electrical connection in an electrical switching device, and an improved electrical switching device.

[0008] The problem is solved according to the invention by a vacuum switching tube with the features of claim 1 and an electrical switching device with the features of claim 10.

[0009] Advantageous embodiments of the invention are the subject of the dependent claims. 2024P18363 DE 2

[0010] A vacuum switching tube according to the invention comprises

[0011] - a housing with an electrically conductive terminal body, wherein

[0012] - the connection body has an external connection geometry for a detachable clamping connection for electrical and mechanical contacting of the vacuum switching tube.

[0013] A vacuum switching tube according to the invention enables electrical and mechanical contacting of the vacuum switching tube via a clamp connection. For this purpose, the housing of the vacuum switching tube has an electrically conductive terminal body with an external connection geometry for the clamp connection. The clamp connection eliminates the need for a screw connection for the electrical and mechanical contacting of the vacuum switching tube. This also eliminates the aforementioned disadvantages of such a screw connection, namely the risk of damaging the thread during the manufacturing process of the vacuum switching tube, the need for time-consuming thread cleaning, the extensive testing required for the thread, and the potential unusability of the vacuum switching tube due to thread damage. Furthermore, the clamp connection simplifies and speeds up the installation of the vacuum switching tube compared to a screw connection.Furthermore, manufacturing costs for the vacuum switching tube are reduced, as no thread needs to be machined or soldered into or onto the tube. The electrically conductive design of the housing's terminal block advantageously allows for both mechanical and electrical connection of the vacuum switching tube via the clamping connection.

[0014] In one embodiment of a vacuum switching tube according to the invention, the connection geometry of the terminal body is formed by a groove that runs annularly around a longitudinal axis of the housing. A groove is a very simple and cost-effective means of enabling a clamping connection. For example, a clamping device can engage in the groove for clamping.

[0015] In a further embodiment of a vacuum switching tube according to the invention, the connecting body comprises an end region of the housing. This embodiment of a vacuum switching tube according to the invention takes into account that the switching contacts of a vacuum switching tube are each led to an end region of the vacuum switching tube and therefore electrical contacting of a switching contact in an end region of the vacuum switching tube is particularly simple. 2024P18363 DE 3

[0016] In a further embodiment of a vacuum switching tube according to the invention, the terminal body is made of copper or stainless steel. Manufacturing the terminal body from copper is advantageous for the electrical connection of the vacuum switching tube due to copper's high electrical conductivity. Manufacturing the terminal body from stainless steel is advantageous due to stainless steel's high strength when the clamping connection is subjected to high forces.

[0017] In a further embodiment of a vacuum switching tube according to the invention, the housing comprises an insulating body made of an electrically insulating material, for example a ceramic material, and formed in a tube-like shape around a longitudinal axis of the housing. The terminal body has a shielding section projecting into the interior of the housing, which is ring-shaped around a longitudinal axis of the housing and shields a portion of an inner surface of the insulating body. The interior of the housing refers to a space enclosed by the housing. The inner surface of the insulating body refers to the surface of the insulating body facing this space.

[0018] The aforementioned embodiment of a vacuum switching tube according to the invention takes into account that the inner surface of the insulating body must be protected against deposition by metal vapor, which arises from the vaporized surface material of the switching contacts of the vacuum switching tube when electrical currents are switched. Typically, the inner surfaces of insulating bodies in vacuum switching tube housings are protected from the metal vapor by metal shields, which are manufactured from stainless steel or copper sheets using a deep-drawing process. This manufacturing of the metal shields entails high tooling costs. Adapting the geometries of the metal shields to the respective vacuum tube is therefore very complex. Furthermore, the metal shields are generally connected to other components of the vacuum switching tube by soldering.Suitable surfaces are required for the solder joints, which are usually produced by separate turning operations on the components. This causes additional effort in the manufacture of vacuum switching tubes. In the inventive embodiment of the terminal body with a shield section that shields part of the inner surface of the insulating body, the terminal body also provides shielding of the inner surface of the insulating body, so that separate metal shields for shielding the insulating body can be at least partially eliminated. This reduces the number of components of the vacuum switching tube. Furthermore, the step of positioning and fixing these metal shields in the housing, for example by DE 4, is eliminated.

[0019] Soldered connections. This reduces the effort and cost of shielding the inner surface of the insulating body.

[0020] In a further embodiment of a vacuum switching tube according to the invention, the terminal body is connected to an annular, flat contact surface of the insulating body, the normal vector of which is parallel to the longitudinal axis of the housing. The width of the contact surface perpendicular to the longitudinal axis of the housing is, for example, smaller than the thickness of the insulating body in a plane perpendicular to the longitudinal axis of the housing. According to this embodiment of a vacuum switching tube according to the invention, the terminal body and the insulating body are connected only in a relatively small contact area. This is particularly advantageous if the insulating body and the terminal body are made of materials with very different coefficients of thermal expansion, since the small contact area reduces stresses resulting from temperature changes, especially in the insulating body.

[0021] In a further embodiment of a vacuum switching tube according to the invention, the connecting body comprises a fixed contact of the vacuum switching tube. This advantageously further reduces the number of components of the vacuum switching tube and the effort required for its manufacture and assembly.

[0022] Another embodiment of a vacuum switching tube according to the invention has a moving contact made of copper and a fixed contact made of stainless steel.

[0023] Another embodiment of a vacuum switching tube according to the invention has a moving contact made of stainless steel and a fixed contact made of copper.

[0024] An electrical switching device according to the invention comprises a vacuum switching tube designed according to the invention and a clamping device that interacts with the connection geometry of the terminal body of the vacuum switching tube for electrically and mechanically contacting the vacuum switching tube. For example, the switching device is a contactor or a tap changer of a transformer. The advantages of an electrical switching device according to the invention result from the advantages of a vacuum switching tube according to the invention mentioned above.

[0025] The properties, features and advantages of this invention described above, as well as the manner in which they are achieved, are explained more clearly and distinctly in DE 2024P18363 5.

[0026] This relates to the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. These show:

[0027] FIG 1 shows a sectional view of a first embodiment of a vacuum switching tube according to the invention,

[0028] FIG 2 shows a sectional view of a second embodiment of a vacuum switching tube according to the invention,

[0029] FIG 3 shows a block diagram of an embodiment of an electrical switching device according to the invention.

[0030] Corresponding parts are marked with the same reference symbols in the figures.

[0031] Figure 1 (FIG 1) shows a sectional view of a first embodiment of a vacuum switching tube 1 according to the invention. The vacuum switching tube 1 comprises a housing 3 with an insulating body 5 and a terminal body 6, a moving contact 9 and a bellows 11.

[0032] The insulating body 5 is made of an electrically insulating material, for example a ceramic material, and is tubular, essentially hollow cylindrical, around a longitudinal axis 13 of the housing 3.

[0033] The terminal body 6 is manufactured in one piece from a metal, for example copper or stainless steel. The terminal body 6 comprises an end section 15 of the housing 3, a shield section 17, and a fixed contact 19 of the vacuum switching tube 1, and has an external connection geometry 7 for a detachable clamp connection for electrical and mechanical contacting of the vacuum switching tube 1. The connection geometry 7 is formed by a groove 8 that runs annularly around the longitudinal axis 13 of the housing 3.

[0034] The shielding section 17 is ring-shaped around the longitudinal axis 13 of the housing 3 and shields part of an inner surface 21 of the insulating body 5. The shielding section 17 has an opening 23 whose diameter decreases monotonically with increasing distance from the end region 15 of the housing 3. 2024P18363 DE 6

[0035] The fixed contact 19 is arranged on an inner surface of the end region 15 of the housing 3 and faces the moving contact 9. An inner surface of the end region 15 of the housing 3 has a ring-shaped recess 29 extending around the fixed contact 19.

[0036] The connecting body 6 is connected to an annular, planar contact surface 25 of a first end 26 of the insulating body 5 facing the end region 15 of the housing 3, wherein a normal vector N of the contact surface 25 is parallel to the longitudinal axis 13 of the housing 3. The width of the contact surface 25 perpendicular to the longitudinal axis 13 of the housing 3 is less than the thickness of the insulating body 5 in a plane perpendicular to the longitudinal axis 13 of the housing 3.

[0037] The moving contact 9 is bolt-shaped and made of an electrically conductive material, for example, stainless steel. The moving contact 9 is movable relative to the housing 3 and the fixed contact 19 by axial displacement along the longitudinal axis 13 of the housing 3 between a first switching position shown in Figure 1, in which one end of the moving contact 9 rests against the fixed contact 19, and a second switching position, in which the moving contact 9 is spaced apart from the fixed contact 19.

[0038] The bellows 11 is arranged around a section of the moving contact 9. A first end 27 of the bellows 11 is firmly and gas-tightly connected to a second end 30 of the insulating body 5, which faces away from the end region 15 of the housing 3. A second end 28 of the bellows 11 is firmly connected to a flange 31, which runs annularly around the moving contact 9 and is connected to it.

[0039] Figure 2 (FIG 2) shows a sectional view of a second embodiment of a vacuum switching tube 1 according to the invention. The vacuum switching tube 1 again comprises a housing 3 with an insulating body 5 and a terminal body 6, a moving contact 9 and a bellows 11.

[0040] The embodiment of a vacuum switching tube 1 shown in Figure 2 differs from the embodiment shown in Figure 1 essentially only in the design of the terminal body 6. Apart from that, the vacuum switching tube 1 of this embodiment is designed like the vacuum switching tube 1 of the embodiment shown in Figure 1.

[0041] In this embodiment, the connecting body 6 comprises a contact rod 33, which extends from the end region 15 of the housing 3 outwards along the longitudinal axis 13 of the housing 32024P18363 DE 7

[0042] protrudes. The contact rod 33 enables contact with the fixed contact 19 at a greater distance from the housing 3.

[0043] The connecting body 6 of the embodiments shown in Figures 1 and 2 is manufactured, for example, by turning and / or milling from a workpiece, for example from a copper block, or by additive manufacturing.

[0044] Figure 3 (FIG 3) shows a block diagram of an embodiment of an electrical switching device 37 according to the invention. The switching device 37 comprises a vacuum switching tube 1, which is configured according to one of the embodiments shown with reference to Figures 1 or 2, and a clamping device 39, which interacts with the connection geometry 7 of the terminal body 6 of the vacuum switching tube 1, for electrically and mechanically contacting the vacuum switching tube 1. Further components of the switching device 37 are not shown in Figure 3. The switching device 37 is, for example, a contactor or a tap changer of a transformer.

[0045] Although the invention has been further illustrated and described by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. 2024P18363 DE 8

[0046] Reference symbol list

[0047] I Vacuum switching tube

[0048] 3 cases

[0049] 5 insulating bodies

[0050] 6 connection bodies

[0051] 7 Connection geometry

[0052] 8 Nut

[0053] 9 Moving contact

[0054] II Bellows

[0055] 13 Longitudinal axis

[0056] 15 End area of ​​the housing

[0057] 17 Umbrella section

[0058] 19 fixed contacts

[0059] 21 Inner surface of the insulating body

[0060] 23 Opening

[0061] 25 contact area

[0062] 26 first end of the insulating body

[0063] 27 first end of the bellows

[0064] 28 second end of the bellows

[0065] 29 In-depth study

[0066] 30 second end of the insulating body

[0067] 33 Contact rod

[0068] 31 flange

[0069] 37 Switching device

[0070] 39 Clamping device

[0071] N normal vector

Claims

2024P18363 DE 9 Patent claims 1. Vacuum switching tube (1), comprising - a housing (3) with an electrically conductive terminal body (6), wherein - the connection body (6) has an external connection geometry (7) for a detachable clamping connection for electrical and mechanical contacting of the vacuum switching tube (1).

2. Vacuum switching tube (1) according to claim 1, wherein the connection geometry (7) is formed by a groove (8) which extends in an annular manner around a longitudinal axis (13) of the housing (3).

3. Vacuum switching tube (1) according to claim 1 or 2, wherein the connecting body (6) comprises an end region (15) of the housing (3).

4. Vacuum switching tube (1) according to one of the preceding claims, wherein the connecting body (6) is made of copper or stainless steel.

5. Vacuum switching tube (1) according to one of the preceding claims, wherein the housing (3) has an insulating body (5) made of an electrically insulating material and designed as a tube around a longitudinal axis (13) of the housing (3), and the terminal body (6) has a shielding section (17) projecting into the interior of the housing (3), which is designed as an annular shape around the longitudinal axis (13) of the housing (3) and shields a part of an inner surface (21) of the insulating body (5).

6. Vacuum switching tube (1) according to claim 5, wherein the terminal body (6) is connected to an annular planar contact surface (25) of the insulating body (5), the normal vector (N) of which is parallel to the longitudinal axis (13) of the housing (3).

7. Vacuum switching tube (1) according to claim 6, wherein a width of the contact surface (25) perpendicular to the longitudinal axis (13) of the housing (3) is less than a thickness of the insulating body (5) in a plane perpendicular to the longitudinal axis (13) of the housing (3).

8. Vacuum switching tube (1) according to one of the preceding claims, wherein the connecting body (6) comprises a fixed contact (19) of the vacuum switching tube (1). 2024P18363 DE 10 9. Vacuum switching tube (1) according to claim 8 with a moving contact (9), wherein the moving contact (9) is made of copper and the fixed contact (19) is made of stainless steel or the moving contact (9) is made of stainless steel and the fixed contact (19) is made of copper.

10. Electrical switching device (37) comprising a vacuum switching tube (1) designed according to one of the preceding claims and a clamping device (39) cooperating with the connection geometry (7) of the terminal body (6) of the vacuum switching tube (1) for electrical and mechanical contacting of the vacuum switching tube (1).

11. Switching device (37) according to claim 10, which is a contactor or a tap changer of a transformer.

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